miR-30a-5p induces Aβ production via inhibiting the nonamyloidogenic pathway in Alzheimer’s disease

Alzheimer's disease (AD) pathogenesis is known to involve a dysregulation of microRNA expression, and these intricate transcriptional cascades between multiple pathological manifestations affect brain homeostasis. Previous studies have revealed that miR-30a-5p participates in neuronal damage and is upregulated in amyloid beta-peptide (Aβ)-induced models. However, its involvement in cognition dysfunction and the AD pathogenic process remains unclear. In the present study, we investigated the mechanisms underlying miR-30a-5p involvement in AD, and its potential as a therapeutic target. Our results reveal that miR-30a-5p was substantially upregulated during the pathological progression of AD, presenting as an increased level in the cortex and hippocampus of APP/PS1 and five familial AD mice, AD cells, and the plasma of AD patients. miR-30a-5p overexpression also induced neuronal injury and apoptosis in AD cells. Mechanistically, miR-30a-5p negatively regulated ADAM10 and SIRT1 by directly binding to their 3'-untranslated regions. A possible association between SIRT1 and ADAM10 was observed via their rescue of miR-30a-5p-induced RARβ downregulation. Interestingly, miR-30a-5p was observed to inhibit the nonamyloidogenic pathway by down regulating ADAM10 and SIRT1, thus promoting Aβ1-42 overproduction. In APP/PS1 mice, knockdown of miR-30a-5p ameliorated cognitive dysfunctions and neurodegenerative changes, suppressed Aβ accumulation, and inhibited Aβ1-42 generation by enhancing the nonamyloidogenic pathway via upregulation of ADAM10 and SIRT1. However, these improvements were blocked by ADAM10 and SIRT1 silencing. In conclusion, the present study implicates dysregulation of the miR-30a-5p/ ADAM10/ SIRT1 pathway as a critical mediator of AD pathogenesis, highlighting the importance of epigenetics and identifying novel therapeutic targets in the nonamyloidogenic pathway.